Heretofore, in the portable engine, a cover of a casing for containing the engine is fixed to the casing with a screw and an inlet of a fuel tank contained in the casing is provided outside upper portion of the casing passing through the casing. Arrangement is such that, in use, it is inconvenient for the operator to fix or remove the cover of the casing further, it tend to soil the operator's clothes and others because the fuel is often spilt over the surface of the casing adjacent the inlet of the fuel.
Further, in a recoil starter of the engine of this type, a reel is rotatably supported by a supporting member fixed to the casing. In order to prevent removal of the reel from the supporting member, a snap ring is provided to engage an end portion of the supporting member and/or there is provided a bolt screw connected to the end portion of the supporting member to prevent removal of the reel through a washer from the supporting member. In either case, the structure is rather complicated and time consumable. Further in the engine of this type, an ignition plug must be removed to confirm if the secondary circuit is properly applied with current when the engine does not start to operate in spite of the ignition action is taken.
Further, the engine of this type has such defect in which the fuel is excessively absorbed and consequently the ignition can not be carried out satisfactorily when the engine is started to operate through the recoil starter with the switch is erroneously connected.